Fire alarm



April 7, 1931. M. L. DoUGHx-:RTY

FIRE ALARM y 2 Sheets-Sheet l Filed May 25, l928- SEQ 1 v f/r, u 0 N A .w W f z/ n a .J Z m/M 2 J f 2 Z L| N K April 7, 1931- M. DQUGHERTY 1,799,583

FIRE ALARM F'iled May 25, 1928 2 Sheets-Sheet 2 l? ooooooldoo' oooo'oooop a H TI i /z 45 5ft-5 of Fig. s.

Patented Apr. 7, 1931 UNITED STATES PATENT OFFICE l FIRE ALARM Application led Hay 23,

' My `invention relates to automatically operated lire alarm systems and has for its object generally to provide an electrically operated and controlled alarm, adapted to be set ofi' by excessive heat within the building protected by the alarm.

More/particularly, it is my object to provide an electrically controlled alarm, including an alarm device such. as a bell or the like,

'10 a switch adapted to close a circuit through said bell and means actuated by excessive heat within the building to close said switch.

More particularly, it is my object to provide such a :dre alarm in which a single conkl5 trol switch is adapted to be actuated by any 'oit a series ci devices, each one located in a different portion of the building and sensitive to excess heat.

l further object is to provide a lire alarm 2@ system which is simple, durable and inexpensive in construction; A

Another object is to provide such a Ilire alarm system which is positive and sure in operation and which will not readily get out 25 oi' order'. y

With these and other objects in view, my invention consists in the construction, arrangement and combination ot the various p parts ci" my device, whereby the objects con- 3@ templated are attained, as hereinafter more fully set forth, pointed out in my claim, and illustrated in the accompanying drawings, in which: l i Fig. 1 is a plan view in section of a build- 35 ing installed with the lire alarm of my invention. f

. Fig. 2 is a sectional view throughthe inaster switch, the remainder 'of the system being shown Ain diagram.

Fig. 3 is a sectional line 3 3 of Fig. 2.

Fig. 4 is a sectional view taken on the line Het Fig. 2.

Fig. 5 is a sectional vview taken on the view taken .on the line 1Fig. 6 is a plan view of the master switch. l. Figj is a detaiL'sectional view through one of the remote control switches."

l Fig. 8 is a sectionalview through the ceil- 5"..ing` of a building installed with my inven- 1928. Serial No. 280,07.

tion, illustrating a series of remote control switches.

Fig. 9 is an elevational view, partly in section, of a portion of the interior of a building installed with my invention, the master switch and portions of its connections being shown.

Fig. 10 is a detail, sectional view through the fusable pipe control for the master switch. ln the accompanying drawings, I have used thereference character 10 to indicate generally the walls of a building which is to be equipped with the fire alarmsystem of my invention.

The ceiling of the building is indicated at x 11 in Fig. 8.

n The protective alarm system of my invent1on includes a series of external alarm devices, such as the bells or buzzers 12, which are 7connected by wires 13 to the master switch and which are grounded, as at 14.

A source of current 15 is used to energize the bells 12 and preferably is comprised in the ordinary electric lighting and power circuit with which every building is supplied. The source of current 15 is connected to the .master switch by means oi a wire 16.

The master switch includes a casing or box 1'?, having a removable cover 18, which is preferably of insulating material. In the bottom of the box 17 is mounted the master switch proper, including a switch blade 19, a

v fork 20, to receive the plate 19, a bracket 21,

to which the blade 19 is tulcrumed and binding posts 22 and 23,by means of which the wires 16 and 13, respectively, are connected to the switch blade 19 and to the fork 20.

The bracket 21 and the fork 20 are pretmounted on an insulating base 24, se-

erabl y cureclly to the bottom l? of the casing. Any w means forproperly mounting these members and insulating them from the casing might be employed.`

A series of remote control elements are pro= 'Y vided for actuating the master switch and these remote control elements are divided into 1 two types. i The first type of remote control comprises a plurality of fusible pipes 25, illustrated in` Figs..9 and 10, secured by brackets 26 to the walls, the ceiling and the floor of the building and extending 1n. all directions and covering all regions of the walls.

Within each fusible tube is a fabric cord 27, which extends the entire length of the tube, is secured at the remote end of the tube and at the other end of the tube extends through the open end thereof to be secured to the levers 29 on the switch box.

The levers 29 are fulcrumed upon brackets 30, which are secured to the cover 18 of the master switch box. These levers are ar.- ranged in radial positions, radiating from a common center which is in the axis of a lunger 31, having a broad head 32, engaged )y the inner ends of the levers 29. The cords 27 may be secured to the outer ends of the levers 29 when the cords extend downwardly from the levers or to the inner ends of the levers 29 when the cords extend upwardly from the levers, both as shown in Fig. 2.

Tension springs 33 are connected between the inner ends of the levers and the cover 18 of the master switch box and the levers are held against the pull of the springs by means of the cords 27. The lower end of the plunger 31 engages the switch blade 19 through the medium of an insulating saddle 34, shown in prongs of the section in Fig. 4 andupon release of one of the cords 27, its corresponding lever will depress the plunger 31, causing the switch knife 19 to be moved into engagement with the switch fork 20, closing the switch.l

Upon closingof the master switch, the alarm elements 12 will be actuated, giving notice of the presence of a ire in the building.

The cords 27 are released by the heat from the lire, fusing the soft lead of the pipes 25 and burning through the cords. Y

-Inaddition to the alarm elements 12, my system preferably includes a drop board 35, having signal elements 36, which is installed in the fire station in the district in which the building is located. Upon the drop board 35 are mounted a plurality of signal elements 36, one of which is connected to the particular building in which the particular alarm system is located, as bythe wire 37. The other elcments 36 will be connected to other similar alarm systems in other buildings.

It will be readily seen that the signal elements 36 will be. energized coincidentally with the alarm elements 12.

Referring to Fig. 1, it will be noted that the wire 16 which carries the current to the master switch box is carried on the outside of the building from the metal or source of current 15 to the switch box and that the switch box is located in one corner of the .building where it probably will be the last to be reached by the fire. From this position, the pipes 25 radiate in directions over the floors, the walls and the ceiling of the building.

The pipes, when they are used on the l'ioors, will be preferably lset in depressions or troughs formed in the floors, said troughs being open at the surface of the floor and the pipes bein made flat on'the upper side so as to rest ush with the surface of the floo and yet to be exposed to the fire.

It may now be noted that the arrangement is such that the release'of a single cord 27' will actuate the master switch and cords are all connected in parallel to the single switch. The word parallel is used here to indicate that each individual cord begins at the switch and terminates at a remote point from the switch, none of the various cords or pipes being connected together.

Consequently, the cords may be made as short as 1s necessary in order to obtain the desired ease of operation. If the pipes were made too long and caused to wind back-and forth, the release of the cord at one end might not actuate the. switch, due to the large amount offriction between the cord and the pipe in the many and varied windings thereof.

Where it -is necessary to put a bend in the pipe, a 'set of pulleys 39 are provided to carry the cord around the bend. (See Fig. 10.)

yet the 1 In place of the drop board 35 in the lire Y station, a telephone switch board could be used for the same purpose. Each lire station will be provided with an alarm bell 12 to immediately call attention to the fire and the drop board will indicate the particular building to which the fire is located, each 'signal element 36 being numbered to correspond with its particular building.

I provide an independent system of remote controls, which can be hung in various positions between the floor and ceiling of a room near tables of merchandise, etc. This sec ond remote control system comprises a plurality of remote control switches, one of which is shown inFig. 7.

Each remote control switch comprises an insulating base 40, Iin which are secured a pair of binding posts 4 1 and 42,?the formercarrying a bracket 43, on which is mounted a switch lever 44 and the latter having va switch point 45, adapted to coact with the` switch point 46 of the lever 44. The switch y points 45 and 46 are of some non-corrosive metal such as tungsten. A heat-proof, transparent' covering of isin-glass or the like 47 by a'fusible link 49, connecting the extended i end of the lever withl a suitable linger 50, secured to the base 40.

These remote control switches are sus-` pended by wires 51, secured to the binding posts 41 and 42 and to the line wires 52 and 53, suspended from suitable ceiling brackets '54. Thus the wires 51 serve not only to sup port the switches in the proper position but members adapted to be severed by excess also as links in the circuit including the heat.

switches. Signed this 21st day of May, 1928, in the It will be noted that the'switches are all county of Woodbu and State of Iowa. 5 arranged in parallel so that any one of the MICHAE L. DOGHERTY. 70

switches on closing will close the circuit through the line wires 52 and 53 see Fig. 2). The source of current 15 anda motor 54, which is adapted to close the master switch. The motor 54 is a. very small, electrical 75 motor and is provided with a cam 55, mounted upon its shaft in a position to act upona lever 56, fulcrumed upon a bracket 57, mounted within the switch box 17. The other end of the lever 56 is forked 80 to engage the switch blade 19.

Upon one revolution of the armature of the motor, the end of the switch lever 56, engaged b the cam, will be raised and its y other end epressed, forcing the switch blade 85 19 in-to closed position.'

After the switch has been closed, the motor may continue to operate as long as its circuit remains closed without interfering with the operation of the master switch. 90

By using the motor, the circuit to the alarm elements 12 and 36 will be made by the master switch, which is positioned away rom the most likely region of intense heat. The operation of the remote control switches is 95 practically instantaneous, the fusible link 49 giving way before the wires 52 or 53 will burn through and after the motor has once made a revolution it does not matter if the wires 52 and 53 do burn through. The mas- 100 ter switch having been closed, the alarm circuit is definitely established. The switch blade 19 is normally held open by the friction between the blade and bracket 21, which may be controlled by a single nut 60, ex' 105 erting pressure between the two.

Some changes may be made in the construction and arrangement of the parts of my invention without departing from the real spirit and purpose of my invention, and 110 it is my intention to cover by my claim, any modified forms of structure or use of mechanical equivalents, which may be reason- 50 ably included within its scope.

I claim as my invention:

In a lire alarm, a knife switch, a casing for said switch, a removable cover of insulating material for said casing, a plunger slidably mounted in said cover and provided 120 with a broad head, a saddle of insulating material providedat one end with a socket receiving the inner end of the plunger and provided at its other end with a slot receiv- BO ing the blade of the switch, a plurality of 125 levers independently spring urged in a direction to depress said plunger, each lever havmg a finger resting on the face of said plunger, and means for retaining said levers m inoperative position including tension no 

